asp.net core mvc Razor +dapper 增删改查，分页（保姆教程）

说明：本demo使用sqlserver数据库，dapper orm框架 完成一张学生信息表的增删改查，前端部分使用的是Razor视图，
Linq分页 HtmlHelper。（代码随便写的，具体可以自己优化）
//实现效果如下（首页）

//新增页

//修改页

//删除

1.使用visual stuido 2022创建 asp.net core mvc项目（选择如下图）

2.安装dapper nuget包（选择第一个）

3.使用sqlserver创建数据库和数据表

USE [stu]
GO

/****** Object:  Table [dbo].[StuInfo]    Script Date: 2023/9/28 18:17:23 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[StuInfo](
	[Id] [int] NULL,
	[Name] [nchar](10) NULL,
	[Sex] [nchar](10) NULL,
	[Age] [int] NULL,
	[BirthDate] [date] NULL
) ON [PRIMARY]
GO

4.在项目appsetting中配置数据库连接字符串（填写自己的用户名和密码，和数据库信息）

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "connectionString": "Data Source=.;Initial Catalog=stu;User ID=sa;Password=pe123;TrustServerCertificate=true"
  }
}

5.创建数据学生信息实体类

namespace mvccore.dataModel
{
    public class StuInfo
    {
        public int Id { get; set; }
        public string? Name { get; set; }
        public string? Sex { get; set; }
        public int Age { get; set; }
        public DateTime BirthDate { get; set; }
    }
}

6.创建学生信息dto类

namespace mvccore.ViewModel
{
    public class stuViewModel
    {
        public int Id { get; set; }
        public string? Name { get; set; }
        public string? Sex { get; set; }
        public int Age { get; set; }
    }
}

7.创建stu的接口和实现类service(使用ioc注入面向接口编程)
创建接口和实现类后需要在program中注入服务

using mvccore.dataModel;
using mvccore.ViewModel;

namespace mvccore.service
{
    public interface Istuservice
    {
        //查询
        List<stuViewModel> stuls();

        void save<T>(T stu);

        void edit<T>(T t);

        //删除
        void delete(int Id);

        //根据Id查询
        stuViewModel GetById(int Id);
    }
}

using mvccore.ViewModel;
using Dapper;
using Microsoft.Data.SqlClient;
using System.Collections.Generic;
using System.Collections;
using mvccore.dataModel;

namespace mvccore.service
{
    public class stuservice : Istuservice
    {
        private readonly IConfiguration _configuration;
        public string connstring { get; set; }

        public stuservice(IConfiguration configuration)
        {
            _configuration = configuration;
            connstring = _configuration.GetConnectionString("connectionString");
        }

        //删除
        public void delete(int Id)
        {
            using (var connection = new SqlConnection(connstring))
            {
                string sql = "delete from StuInfo where Id=@Id";
                connection.Execute(sql, new { Id });
            }
        }

        //显示所有列表
        public List<stuViewModel> stuls()
        {
            using (var connection = new SqlConnection(connstring))
            {
                string sql = "select * from StuInfo";
                var list = connection.Query<stuViewModel>(sql).ToList();
                return list;
            }
        }

        //新增
        public void save<T>(T stu1)
        {
            var stu = stu1 as stuViewModel;
            using (var connection = new SqlConnection(connstring))
            {
                string sql = "insert into StuInfo(Id,Name,Sex,Age) values(@Id,@Name,@Sex,@Age);";
                DynamicParameters parameters = new DynamicParameters();
                parameters.Add("Id", 20);
                parameters.Add("Name", stu.Name);
                parameters.Add("Sex", stu.Sex);
                parameters.Add("Age", stu.Age);
                connection.Execute(sql, parameters);
            }
        }

        //编辑
        public void edit<T>(T t)
        {
            var stu = t as stuViewModel;
            string sql = "update StuInfo set Name=@Name,Age=@Age WHERE Id=@Id";
            using (var connection = new SqlConnection(connstring))
            {
                connection.Execute(sql, new { Name = stu?.Name, Age = stu?.Age, Id = stu?.Id });
            }
        }

        //根据Id查询
        public stuViewModel GetById(int Id)
        {
            string sql = "select * from StuInfo where Id=@Id";
            using (var connection = new SqlConnection(connstring))
            {
                var list = connection.Query<stuViewModel>(sql, new { Id = Id }).FirstOrDefault();
                return list;
            }
        }
    }
}

8.创建分页类

namespace WebApplication4
{
    public class PaginatedList<T> : List<T>
    {
        public int PageIndex { get; private set; }
        public int TotalPages { get; private set; }

        public PaginatedList(List<T> items, int count, int pageIndex, int pageSize)
        {
            PageIndex = pageIndex;
            TotalPages = (int)Math.Ceiling(count / (double)pageSize);

            this.AddRange(items);
        }

        public bool HasPreviousPage => PageIndex > 1;

        public bool HasNextPage => PageIndex < TotalPages;

        public static PaginatedList<T> Create(IQueryable<T> source, int pageIndex, int pageSize)
        {
            var count = source.Count();
            var items = source.Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList();
            return new PaginatedList<T>(items, count, pageIndex, pageSize);
        }
    }
}

-------------------------------至此所有的业务代码就准备好了，接下来下控制器和视图里面的代码--------------------------------------------
9.创建stu的控制器
RedirectToAction(“StuInfoList”)：是指定跳转到当前控制器下的其他视图，这里我们跳转到首页

using Microsoft.AspNetCore.Mvc;
using mvccore.service;
using mvccore.ViewModel;
using WebApplication4;

namespace mvccore.Controllers
{
    public class StuController : Controller
    {
        private readonly Istuservice _stuservice;

        public StuController(Istuservice stuservice)
        {
            _stuservice = stuservice;
        }
        //学生列表视图
        public IActionResult StuInfoList(int? pageNumber = 1)
        {
            var list = _stuservice.stuls().ToList();
            int pageSize = 3;
            return View(PaginatedList<stuViewModel>.Create(list.AsQueryable(), pageNumber ?? 1, pageSize));
        }
        //保存视图
        public IActionResult Save()
        {
            return View();
        }
        //保存方法
        public IActionResult Save2(stuViewModel stu)
        {
            _stuservice.save<stuViewModel>(stu);
            return RedirectToAction("StuInfoList");
        }
        //删除方法（正式项目我们一般使用逻辑删除，不会真的把数据删掉）
        public IActionResult delete(int Id)
        {
            _stuservice?.delete(Id);
            return RedirectToAction("StuInfoList");
        }

        //编辑回显
        public IActionResult edit(int Id)
        {
            return View(_stuservice.GetById(Id));
        }
        //编辑方法
        public IActionResult edit2(stuViewModel stu)
        {
            _stuservice?.edit(stu);
            return RedirectToAction("StuInfoList");
        }
    }
}

10.添加首页的视图（StuInfoList.cshtml）

@model PaginatedList<mvccore.ViewModel.stuViewModel>
@Html.ActionLink("新增","Save","Stu")
<table class="table">
    <tr>
        <th>Name</th>
        <th>Age</th>
        <th>Sex</th>
        <td>操作</td>
    </tr>
    @foreach (var item in Model)
    {
        <tr>
            <td>@item.Name</td>
            <td>@item.Age</td>
            <td>@item.Sex</td>
            <td> @Html.ActionLink("编辑","edit","Stu",new{item.Id})   @Html.ActionLink("删除","delete","Stu",new{@item.Id},new { onclick="return confirm('是否删除')" })</td>
        </tr>
    }

</table>
@{
    var prevDisabled = !Model.HasPreviousPage ? "disabled" : "";
    var nextDisabled = !Model.HasNextPage ? "disabled" : "";
}

<a asp-action="StuInfoList"
  
   asp-route-pageNumber="@(Model.PageIndex - 1)"
  
   class="btn btn-default @prevDisabled">
    Previous
</a>
<a asp-action="StuInfoList"

   asp-route-pageNumber="@(Model.PageIndex + 1)"
 
   class="btn btn-default @nextDisabled">
    Next
</a>

11.添加新增视图（Save.cshtml）

<form action="/stu/Save2" method="post">
姓名：<input type="text" name="Name" />
年龄：<input type="text" name="Age"/>
性别:<input type="text" name="Sex"/>
<input type="submit" value="保存"/>
</form>

12.添加编辑视图（edit.cshtml)（可以和新增公用一个视图）

@using mvccore.ViewModel
@model stuViewModel;
<form action="/stu/edit2" method="post">
    姓名：<input type="text" name="Name" value="@Model.Name" />
    年龄：<input type="text" name="Age" value="@Model.Age" />
    <input type="hidden" name="Id" value="@Model.Id"/>
    <input type="submit" value="保存" />
</form>

13.如果在解决方案中有多个项目的话，需要把当前项目设置为启动项目

14.修改项目默认起始页，默认路由是 /Home/index(根据自己的需要更改)

15.End 至此项目demo就完成了，下面是项目的结构图

代码随便写的，主要是快速入门。这边可以去微软官方文档上学习，有完整的代码实例(网址如下)
https://learn.microsoft.com/zh-cn/aspnet/core/tutorials/first-mvc-app/start-mvc?view=aspnetcore-7.0&tabs=visual-studio